Evaluating the effects of tunnelling on historical buildings: The example of a new subway in Rome

Contracts T2 and T3 of the new Line C of Roma underground will be constructed in the historical centre of the city, in an area of great archaeological, historical and artistic value. Significant problems connected to buried archaeological remnants, the geotechnical characteristics of the soil, excavation below the water table, and the necessity of minimising the effects on the historical and monumental heritage are therefore expected. This lecture illustrates the methods adopted to evaluate the effects of tunnelling on the existing monuments and historical buildings, with particular reference to contract T2. The study of the interaction between construction activities and the built environment was carried out following procedures of increasing complexity: Level 1 green-field analyses were used for a preliminary evaluation of the potential damage; Level 2 2D and 3D FE analyses accounted for the presence of existing buildings and considered possible long-term effects induced by drainage through the tunnels lining. The lecture illustrates the main aspects of this procedure, using the example case study of Palazzo Grazioli.